Work will continue along three general lines: 1) The role of lysosomal enzymes in causing the fibroliferative changes which precede atherosclerosis in aortas will be studied by using animal models and tissue culture studies. 2) Transplantation studies will be continued to determine whether veins from genetically related animals can serve as arterial grafts in replacing diseased arteries. Genetic typing on the donor and receptor animals will be carried out and the graft survival measured. 3) The healing response of blood vessels following endarterectomy will be studied.